1. Field of the Invention
The present invention relates to a magnetic head cleaning mechanism to clean a magnetic head to write information on and to read information from a magnetic tape and a magnetic tape apparatus including the magnetic head cleaning mechanism.
2. Description of the Prior Art
In general, a magnetic tape apparatus includes a mechanism which operates at installation of a magnetic tape cartridge therein to transport a tip end of the magnetic tape wound on a supply reel in the cartridge up to a hub of a take-up reel in the magnetic tape apparatus to fixedly attach the tip end onto the hub.
For such operation, there has been known a mechanism called a threading system or method. According to the threading system, a cam gear and a threading arm to be moved by the cam gear are employed to transport a leader block along a magnetic tape transport path up to a supply reel. Also, after a leader pin installed at a tip end of a magnetic tape is engaged with the leader block, the leader block is transported along the magnetic tape transport path up to a take-up reel. The magnetic tape transport path will be referred to as a threader track hereinbelow.
To keep appropriate reading and writing performance of a magnetic head, it is required to periodically clean the magnetic head.
For this purpose, a mechanism to clean a magnetic head may be configured such that an arm provided with a cleaning brush is disposed in the magnetic tape apparatus at a position where the cleaning brush does not hinder running of the tape in an ordinary state. To clean the magnetic head, the arm is moved to bring the brush into contact with the magnetic head.
In a magnetic tape apparatus employing the threading system, the threading arm moves through an upper or lower position over the threader track or over a region on the side of the magnetic head relative to the threader track.
In a known configuration for this operation, the threader track is arranged between the magnetic head and an arm section including an arm provided with a brush and a driving source to move the arm (reference is to be made to, for example, Japanese Patent Laid-Open Ser. Nos. 2006-155683 and 2006-318563).
As FIG. 1 shows, it is considerable to dispose an arm 101 with a brush 103 on the same side as a magnetic head 105 relative to a threader track 109.
In a configuration example of FIG. 1, a brush link arm 101 is disposed on a cam gear 104 to move a threading arm, not shown. In the brush link arm 101, a pivot 102 is arranged on a first end and a brush 103 is disposed on a second end. The brush link arm 101 turns clockwise or counterclockwise about the pivot 102 attached onto a base, not shown.
The brush link arm 101 includes a projection 121 and the cam gear 104 includes a projection depressing section 120. When a driving source, not shown, drives a gear 110 to rotate, causing the cam gear 104 to turn, the projection depressing section 120 accordingly rotates to depress the projection 121 of the brush link arm 101. As a result, the brush link arm 101 rotates clockwise or counterclockwise.
In response to the rotation of the brush link arm 101 about the pivot 102, the brush 103 on the opposing end of the arm 101 is moved from a standby state shown in FIG. 1(a) via a state of FIG. 1(b) in which the brush is in contact with the magnetic head 105, to a cleaning position shown in FIG. 1(c). Further, according to the rotation of the cam gear 104, the brush 103 moves in the reverse direction.
Next, description will be respectively given of problems of the prior arts.
According to the configurations described in Japanese Patent Laid-Open Ser. Nos. 2006-155683 and 2006-318563, the threader track is arranged between the magnetic head and the arm provided with the brush. Hence, the cleaning brush, the arm, and the driving source are disposed on the side opposite to the side of the magnetic head with respect to the threader track. Therefore, to bring the brush into contact with the magnetic head, it is required to move the brush over the threader track in the cleaning operation. This disadvantageously leads to a longer stroke of the brush.
The brush moving path is a dead space where no parts are to be installed. Hence, it is favorable to reduce the stroke to downsize the apparatus.
To remove the problem of the longer stroke, if the brush and the magnetic head are placed on the same side with respect to the threader track, it is difficult, due to existence of the cam gear to move the threading arm, to install the driving source to move the arm, on the magnet head side.
Further, when the brush is installed on the magnetic head side relative to the threader track and the driving source is arranged on the opposite side of the magnetic head with respect to the threader track, it is structurally difficult to move the brush in this situation. Specifically, according to the configuration of the magnetic tape apparatus using the threading system, the threading arm moves through an upper or lower position over the threader track or over a region on the side of the magnetic head relative to the threader track. Hence, it is difficult to dispose, on the brush disposed on the same side as the magnetic head relative to the threader track, a mechanism to supply power from the driving source installed on the opposite side of the magnetic head with respect to the threader track without causing interference with the threading arm.
Hence, in the configuration example of FIG. 1, the brush 103 is installed on the same side as the magnetic head 105 relative to the threader track 109. In operation, the projection depressing section 120 is directly related to the rotation of the cam gear 104 such that the projection 121 rotates the brush link arm 101.
However, in the standby state of FIG. 1(a), the brush 103 is on the rear surface side of the magnetic head 105 when viewed from the threader track 109. That is, the brush 103 is on the rear side, which is an opposite side of the side of a front surface of the magnetic head 105 to be cleaned.
The brush 103 is moved by the rotation of the brush link arm 101 from the standby state of FIG. 1(a) to the cleaning position of FIG. 1(c). For this purpose, the brush 103 moves through the path while making contact with the magnetic head 105 with the smaller distance to the magnetic head 104 in the brush contact position shown in FIG. 1(b) than in the cleaning position. Hence, during the movement of the brush 103 from the standby state of FIG. 1(a) to the cleaning position of FIG. 1(c), the brush 103 is kept pushed against the magnetic head 105. As a result, it is feared that excessive load is applied to the brush bristle of the brush 103, leading to a disadvantage that life of the bristle is shortened.
Also, according to the configuration, while the distance from the pivot 102 as the fulcrum to the contact point as the point of force between the projection depressing section 120 and the projection 121 is relatively small, the distance from the pivot 102 to the brush 103 as the point of action is relatively large. Hence, when an unstable state appears, there exists a fear that the unstable state becomes worse. It is therefore difficult to position the brush 103 with high precision.